Trigeminal neuropathy as the first symptom of mixed connective tissue disease: case report and literature review.

Mixed connective tissue disease (MCTD) combines features of systemic lupus erythematosus, scleroderma, and polymyositis. Neurologic involvement, including trigeminal neuropathy, is rare. The present report describes isolated trigeminal sensory neuropathy as the initial manifestation of MCTD. Quantitative sensory testing revealed progressive bilateral trigeminal sensory deficits. Laboratory evaluation showed elevated anti-U1 ribonucleoprotein (anti-U1-RNP) antibodies, and clinical examination revealed lymphadenopathy and hand swelling, confirming the diagnosis. No other systemic manifestations were present at onset. The present case highlights considering MCTD in patients with orofacial sensory disturbances and performing comprehensive serologic and clinical evaluation for early diagnosis and management to monitor potential life-threatening complications such as pulmonary hypertension.